Governments do not like to be ruled by markets. Markets force prices higher or lower based on supply and demand and not the desires of policy-makers. There are overshoots and bubbles, but these are usually only determined after the fact and can be a matter of opinion.
We have seen copper prices move off their highs coincident with discussions between Chinese companies and policy-makers who want market prices to be kept in order. What this means is not exactly clear, but there have been issues of excess borrowing against copper stocks by Chinese firms. Additionally, softening in the Chinese economy has reduced pressure on copper after strong imports over the last year.
If global demand increases as the world economy reflates, it will determine price; not the desire of policy-makers. This current price reversal will only be temporary, and the longer-term trend will remain in place.